In general, various types of emulsions in the form of an oil-in-water emulsion or a water-in-oil emulsion have been utilized in wide fields of fiber treatment agents, paints, releasing agents, cosmetics and the like. The aforementioned emulsions are usually produced by emulsifying with various surfactants such as nonionic, anionic, cationic, and amphoteric ionic surfactants, having higher hydrocarbon groups, in many cases.
However, good compatibility between the hydrophobic groups of the aforementioned surfactants and oils, and in particular, polyorganosiloxanes is not necessarily exhibited. For this reason, in many cases of emulsifying oils, and in particular, polyorganosiloxanes, with the aforementioned surfactants, there is a problem in which poor storage stability of emulsions may be obtained if an emulsifier with a high shearing force is not used. Therefore, in order to solve the aforementioned problem, a method for emulsifying with a silicone-based surfactant such as a polyether-modified (poly)siloxane or the like having a siloxane as a hydrophobic group is proposed (see Patent Document 1 to Patent Document 3).
However, even in the case of using the polyether-modified (poly) siloxane, stability of the obtained emulsion was not sufficient yet. Therefore, improvements on stability by means of using together with another surfactant, or using a special emulsifying method, have also been proposed (see Patent Document 4 to Patent Document 7). However, there is a disadvantage in that usage is limited. Therefore, a process for easily producing an emulsion, and in particular, an emulsion of a polyorganosiloxane, exhibiting superior storage stability has been desirable.    Patent Document 1: Japanese Unexamined Patent Application, First Publication No. S61-212321    Patent Document 2: Japanese Unexamined Patent Application, First Publication No. H06-145524    Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2000-086437    Patent Document 4: Japanese Unexamined Patent Application, First Publication No. H06-234918    Patent Document 5: Japanese Unexamined Patent Application, First Publication No. H07-133354    Patent Document 6: Japanese Unexamined Patent Application, First Publication No. H11-148010    Patent Document 7: Japanese Unexamined Patent Application, First Publication No. H11-148011